Low Idle Issue

[Santiago]

I suspect that any change at all as you disconnect the plug means the idle switch and wiring must be OK.  On mine it was only when I disconnected, then shorted out the connector and nothing changed at all, that I knew there must be a problem with the wiring back to the ECU, so the ECU wasn't getting the idea of what it was meant to be doing.
Found a broken wire about 6 inches back from the loom plug.

[TomSan]

A little update on this issue.

I figured that due to Santiagao's advice, that ECU must be getting the message through. I did give the idle screw a full turn (anti-clockwise I think).

Now when starting from cold, the engine sits comfortably at 850rpm. After 20-30 seconds it drops down to 800rpm and sounds rough again. After driving it for a while (15 minutes), the idle get's higher and higher and sits around 925-950.

Interestingly enough, on a hot day, turn the engine off for a few minutes and back on and the rev's are right back down at 800rpm. They very quickly recover, but I thought that was rather odd. Either something is not working right or the last place that I had set up the idle/mixture got it badly wrong.

[Sgt_Lemon]

I would imagine the time of year the car was set up would have an effect on the mix and idle as the air temp and density is different.